Decomposition rate constants of Picea abies logs in southeastern Norway

Decomposition rate constants were estimated from 384 cross sections of Norway spruce (Picea abies (L.) Karst.) logs with base diameter >7.0 cm collected in open areas at five different study sites in southeastern Norway. Fresh wood core samples were taken from 95 standing trees adjacent to the logs to estimate the initial density of these cross sections. Based on this chronosequence, a simple negative exponential function of time showed an average decomposition rate constant for all cross sections of 0.033 per year. Cross-section diameter, ground contact, soil moisture, and aspect were all found to have significant impacts on the decomposition rate constant. For different combinations of these characteristics the decomposition rate constant ranged from a minimum of 0.0165 per year to a maximum of 0.0488 per year.